Gauge block having check valve with orifice

ABSTRACT

A gauge block assembly for use in conjunction with the refilling of high pressure gaseous oxygen cylinders. The gauge block is used in an oxygen transfill header or manifold and includes a gas transfer control unit that allows rapid evacuation of the spent oxygen cylinder but that prevents rapid refilling of the oxygen cylinder with fresh oxygen. The gas transfer control unit includes a valve assembly having a restricted orifice therethrough. During the evacuation process, the check valve opens, bypassing the restricted orifice, to allow rapid evacuation of the oxygen cylinder at a first rate of flow. During the refilling process, the check valve closes. The incoming oxygen must flow through the restricted orifice at a second rate of flow less than the first rate of flow thereby regulating the flow of oxygen.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to the filling of oxygen cylinders and,more particularly, to a gauge block assembly for transfilling of highpressure gaseous oxygen cylinders.

2. Description of the Prior Art

In the medical industry gaseous oxygen contained within high pressurecylinders is frequently utilized. These cylinders come in a variety ofsizes and shapes. Because of the durable construction of the cylindertanks, it is not practical, from an economic or monetary viewpoint, tosimply dispose of the cylinders when the oxygen within them has beenexhausted.

Instead of disposing of the cylinders, the cylinders may be refilledwith gaseous oxygen. In order to refill the cylinders, it is firstnecessary to empty or evacuate any remaining or residual oxygen and/orcontaminants from the cylinder. This is accomplished by applying avacuum to the interior of the cylinder and drawing out the remainingcontents. Once this is complete, a partial vacuum exists inside thecylinder. The now empty cylinder is then refilled with fresh oxygenunder a predetermined pressure.

Because of the nature and use of oxygen contained within high pressurecylinders, the refilling of such cylinders with oxygen is regulated bythe Food and Drug Administration (FDA). One aspect regulated by the FDAis the filling rate of the high pressure oxygen cylinders. A cylinderwill heat as it is filled from a high pressure source. The more rapidlythe cylinder is filled, the higher the temperature will rise in thecylinder due to the heat of compression. Excessive temperatures myresult in the ignition of any combustibles that may be present, as wellas causing structural damage to the cylinders, which can undermine theintegrity of the cylinders. FDA regulations thus set forth a maximumincoming gaseous flow rate for refilling of the cylinders. This flowrate cannot be exceeded.

The full flow cylinder pressures generally fall within 2K-3K PSIG.However, although the FDA regulations state that the cylinders must beevacuated to at least 25 inches (635 MM) of mercury, at seal level, theevacuation flow rate is not a regulated aspect. Thus, the evacuationprocess may transpire unrestricted, flowing at the maximum rate of thetotally open flow valve, while the filling process is restricted to amaximum flow rate.

In view of the FDA regulations, prior art regulators for gas flowcontrol in the refilling of high pressure oxygen cylinders utilize arestricted straight through orifice. This is the gas flow path for boththe evacuation and refilling processes. Because this is the case, theorifice is thus sized to permit the maximum rate of gaseous flow intothe cylinder as allowed by FDA regulations for refilling. This however,also limits the evacuation flow rate. Thus, although the evacuation flowrate is not regulated by the FDA and may therefore transpire at anyrate, the use by prior art devices of a restricted orifice for bothevacuation and refilling in order to adhere to the FDA regulationssetting the maximum refilling flow rate, increases the overall time ittakes to complete the entire refill process.

The evacuation time for three "E" type high pressure cylinders utilizingprior art restricted orifices is found to be approximately 12.5 minutes.Also, the overall process includes refilling the cylinders with oxygen,which would double the time for completing the entire process. Thus,very few cylinders may be refilled in a given period of time.

There is thus a need for decreasing the total overall time necessary tocomplete the entire refilling process in order to be able to processmore cylinders in a given period of time.

It is thus an object of the present invention to decrease the overalltime necessary to evacuate and refill a high pressure cylinder withoxygen.

It is therefore an object of the present invention to provide a gaugeblock assembly for the oxygen transfill process that increases theevacuation flow rate so as to decrease the total evacuation time, whilealso not exceeding the maximum fill rate established by regulation.

SUMMARY OF THE INVENTION

The present invention accomplishes the above objects by providing agauge block assembly for an oxygen transfill system that includes acheck valve assembly with a restricted orifice therethrough.

During the evacuation process, the check valve within the gauge blockopens under a vacuum pressure to allow a first rate of flow around thecheck valve, bypassing the restricted orifice. Then, during therefilling process, the check valve closes under positive pressure suchthat the incoming gas is caused to flow through the restricted orifice.The incoming gas enters at a second rate of flow that is less than thefirst rate of flow, but equal to the maximum rate of flow permitted byregulation.

In one form thereof, the present invention provides a gauge blockassembly for an oxygen transfill apparatus. The gauge block includes abody having a longitudinally extending.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features, advantages, andobjects of the present invention are attained and can be understood indetail, a more particular description of the invention, brieflysummarized above, may be had by reference to the embodiments thereofwhich are illustrated in the appended drawings. Corresponding referencecharacters indicate corresponding parts throughout the several view.

It is noted, however, that the appended drawings illustrate only atypical embodiment of this invention and is therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments. Reference the appended drawings, wherein:

FIG. 1 is an elevational view of a header extension in which is disposeda gauge block having a check valve in accordance with the presentinvention;

FIG. 2 is an enlarged sectional view of a gauge block assembly depictingthe valve subassembly in a filling position;

FIG. 3 is an enlarged sectional view of a gauge block assembly depictingthe valve subassembly in a vacuum pulling position;

FIG. 4 is an enlarged side view of the gauge block taken along line 4--4of FIG. 3;

FIG. 5 is an enlarged sectional view of the restrictor valve element;

FIG. 6 is an enlarged perspective view of the restrictor valve element;

FIG. 7 is an enlarged top view of the filter element;

FIG. 8 is an enlarged side view of the filter element;

FIG. 9 is an enlarged side view of the spring;

FIG. 10 is an enlarged top view of the retaining ring; and

FIG. 11 is an enlarged side view of the retaining ring.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1 there is shown a fill side header extension 20being part of an oxygen transfilling system. Fill side header extension20 includes a tube or conduit 22 with a regulator coupling 36 at oneend. Regulator coupling 36 is adapted to releasably attach to one end ofa supply regulator/gauge assembly (not shown). A supply side headerextension (not shown) is coupled to another end of the supplyregulator/gauge assembly and is adapted to connect to a plurality ofoxygen supply cylinders, typically "H" type cylinders. The "H" typecylinders hold the oxygen for transfilling.

Disposed along the length of conduit 22 is a first valve assembly 24with regulator knob 28 including a contents gauge 26, and a second valveassembly 30 with regulator knob 34 including a contents gauge 32. Itshould be noted that any umber of valve assemblies may be disposed alongconduit 22 for refilling that number of cylinders, but for purposes ofillustration, only two such assemblages are shown. Valve assembly 24 iscoupled to a gauge block housing 40 while valve assembly 30 is coupledto a gauge block housing 42. Likewise, each valve assembly that isconnected to conduit 22 is also coupled to a gauge block housing. Eachgauge block housing 40, 42 includes a gauge block assembly therein,described hereinbelow, in accordance with the present invention.

Fill side header extension 20 is utilized to connect a plurality of andallow fluid communication between spent oxygen cylinders (not shown),typically "E" type oxygen cylinders, via pigtails (not shown) with theoxygen supply cylinders (not shown), typically "H" type cylinders, andwith a vacuum or evacuation pump (not shown). A pigtail connects withthe gauge block housing at one end, and to the cylinder to be filled atthe other end. A supply side header extension (not shown) is coupled viaa regulator (not shown) to connector 36, and is attached via pigtails(not shown) to a plurality of oxygen supply cylinders. In this manner,supply oxygen is furnished to fill side header extension 20 from theconnector 30 side.

A valve assembly (see valve assemblies 24, 30) is provided along conduit22 for every spent oxygen cylinder that the user desires to refillduring a refill operation. Thus, there is a gauge block assembly,described hereinbelow, for each valve assembly. The gauge block assemblyprovides controlled evacuation and refilling of the spent oxygencylinders as explained hereinbelow in connection with the operation ofthe gauge block assembly.

In accordance with the present invention a gauge block assembly 50, oneof which is disposed within each of the gauge block housings of thevalve assemblies, is shown in detail in FIG. 2. Gauge block assembly 50includes a body 52 that is preferably fabricated from brass, but whichcan be of a material that will withstand the applied pressures while atthe same time also not react with oxygen so as to avoid contamination oradulteration thereof. Body 52 includes a first portion 53 and a secondportion 54 disposed at one end of first portion 53 and integrally formedtherewith. First portion 53 has an outer surface of a hexagonal shape(see FIG. 4) and a longitudinal bore 55 therethrough that defines anopening 57 at one longitudinal end opposite second portion 54. Internalthreads 59 are disposed at opening 57 for connection to valve 24 or 30(FIG. 1).

First portion 53 further includes a bore 60 disposed transverse to bore55 that defines an opening 58. Opening 58 has internal threads 61 forthreaded engagement with a gauge (26 or 32 in FIG. 1). At the endproximate second portion 54, bore 55 reduces in diameter via annulartaper 62 to a lesser diameter aperture 64.

Second portion 54 has a generally annular outer surface configurationwith external threads 63 that extend approximately three-quarters of thelongitudinal length thereof. A bore 68 longitudinally extends throughsecond portion 54. Bore 68 includes an annular taper 66 at an endproximate first portion 53 and is in communication with longitudinalbore 55 of first portion 53 via aperture 64. At the end distal taper 66there is formed a ledge 75 that defines the beginning of an opening 56.Bore 68 also defines a valve chamber. Ledge 75 provides a seat forfilter element 74 so that filter element 74 is maintained at opening 56.

Disposed within bore or valve chamber 68 is a longitudinally movablerestrictor or valve element 70 and a spring 72. In a preferred form,valve element 70 is fabricated from brass, but my be formed from anymaterial suitable for the present application. Referring additionally toFIGS. 5 and 6, valve element 70 is generally cylindrical-shaped having afront cylindrical portion 85 and a rear cylindrical portion 86 with ahexagonal portion 84 therebetween. A longitudinal cup-like interior 78is defined from front portion 85 that receives an end of spring 72 whendisposed within valve chamber 68. As can be most easily discerned fromFIG. 5, rear portion 86 includes an orifice, aperture, or restriction 82centrally disposed within conical concavity 80. Restriction 82 is sizedin accordance with permitting a predetermined rate of gaseous flowtherethrough. In accordance with an aspect of the present invention,restrictor 82 is sized according to the FDA regulations for maximumincoming oxygen flow rate.

The hexagon-shape of middle portion 84 permits a controlled flow rate ofgaseous oxygen around restrictor 70 when restrictor 70 is in the openposition as depicted in FIG. 3. This occurs when a vacuum is pulled asexplained in detail hereinbelow in conjunction with the operation of thepresent gauge block assembly.

Spring 72 has one end seated against filter 74 with the other end seatedagainst an end of interior 78. Restrictor 70 is thus normally biased byspring 72 in a closed position.

Filter 74 is shown in detail in FIGS. 7 and 8. In a preferred form,filter 74 is a 50 micron sintered metal bronze filter of 90% copper and10% tin, although it should be appreciated that a filter of anothermaterial may be utilized that does not react with oxygen. Such a filteris manufactured by Avenger Metals, Ipswich, Mass. Filter 74 isdisc-shaped and is sized to snugly but retainingly fit within opening 56and rest on annular ledge 75.

Referring now to FIG. 9 there is shown spring 72. In a preferred form,spring 72 is a 0.011 size wire coil producing a load of 0.063 to 0.077lbs. at a length of 0.250 inches, and manufactured of stainless steeltype 302. It should be recognized that other materials may be utilizedconsistent with the non-reaction requirement with oxygen and within thepounds rating. Spring 72 is not necessary for the operation of the valveassembly. Rather, spring 72 prevents rattling of restrictor element 70and helps to provide proper seating thereof within bore/valve chamber68.

The retaining ring 76 is depicted in FIGS. 10 and 11. Retaining ring 76includes a central ring or hub 88 with a central cutout portion 89. Inthe preferred form, retaining ring 76 is fabricated from a stainlesssteel type PH 15-7Mo or equivalent, although other materials may beutilized that will not react with oxygen. Radially disposed about theperiphery of ring 88 are six flanges collectively labeled 90 thatslightly axially upwardly curve as best seen in FIG. 11. The outsidediameter surface of retaining ring 76 taken about the edges of flanges90 is sized to abut the inside diameter of opening 56. Retaining ring 76functions to retain filter element 74 within opening 56 and seatedagainst ledge 75. When installed, retaining ring 76 is oriented suchthat flanges 90 extend axially outward relative filter element 74.

The manner of operation of the present gauge block assembly will now bedescribed with initial reference to FIG. 2. As depicted in FIG. 2,restrictor 70 is biased via spring 72 into a first position wherein rearportion 86 is seated against annular taper 66. As noted above however,spring 72 is not a necessary component for the operation of the presentgauge block assembly since pressures alone developed during theevacuation and refilling process suffice to actuate restrictor 70.Although spring 72 may serve to bias restrictor 70 into a closedposition, spring 72 also prevents rattling of restrictor 70 withinchamber 68. Thus, since restrictor 70 is totally responsive to thepressures exerted thereon as described hereinbelow, spring 72 need notbe necessary.

FIG. 2 depicts the orientation of gauge block assembly 50 for theorientation of fill side header extension 20 depicted in FIG. 1.Initially, it should be understood that both the vacuum pressure and thepositive supply pressure are applied to opening 56 of gauge blockassembly 50. The spent oxygen cylinders (not shown) are connected to therespective valve assembly via the pigtails. A vacuum pressure is appliedto the cylinders via a vacuum pump (not shown). The vacuum pressure isapplied in order to evacuate any remaining contents from the cylinders.As the vacuum is applied to opening 56, the reduced pressure causesrestrictor 70 to unseat from seat or annular taper 66 regardless of thepresence of spring 72. Referring to FIG. 3, this condition is depicted.Any remaining contents from the cylinders being evacuated may thus flowaround the restrictor 70 between the outside surface of restrictor 70and the inside surface of portion 54 defining chamber 68. Thus, there isan almost unrestricted gaseous flow rate.

When a proper vacuum has been achieved, refilling of the spent cylindersmay proceed. After closing the appropriate valves of the headers andregulators, the new oxygen is caused to flow into opening 56. Thepositive pressure created by the inflow of gas into restrictor 70 causesrestrictor 70 to seat against annular taper 66 such that the gas mustflow through restriction 82. This, then slows down the rate of flow asdetermined by the size of restrictor 82.

For purposes of clarity, the restrictor 70 depicted in FIG. 3 isoriented such that the top outer hexagon surface is essentially parallelto the inner surface of chamber 68 in cross section. This permits theunderstanding of the gas flow pattern around the restrictor 70 when inthe open or vacuum pressure position.

While the foregoing is directed towards the preferred embodiment of thepresent invention, other and further embodiments of the invention may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims which follow.

What is claimed:
 1. A gauge block assembly for gas transfillingapparatus, the gauge block assembly comprising:a body having a first endand a second end, said body including a gas passageway therethroughdefining a first opening in said first end, and a second opening in saidsecond end; gas transfer control means disposed in said gas passagewayfor regulating the flow of gas through said gas passageway, said gastransfer control means adapted to be actuated into a fill position when. .a positive pressure is applied to.!. .Iadd.pressure at .Iaddend.saidfirst opening .Iadd.is greater than pressure at said secondopening.Iaddend., the fill position permitting . .a.!. .Iadd.gas flowthrough the passageway from the first opening to the second opening at afirst .Iaddend.restricted gas flow rate . .between said second openingand said first opening.!., said gas transfer control means adapted to beactuated into an evacuation position when . .a negative pressure isapplied to.!. .Iadd.pressure at .Iaddend.said first opening .Iadd.isless than pressure at said second opening.Iaddend., the evacuationposition permitting . .an unrestricted.!. .Iadd.gas flow through thepassageway from the second opening to the first opening at a second.Iaddend.gas flow rate . .between said first opening and said secondopening,.!. .Iadd.greater than said first gas flow rate.Iaddend., saidgas transfer control means including a valve member adapted to ..restrictively.!. longitudinally move in said gas passageway in a firstdirection . .defining.!. .Iadd.toward .Iaddend.the evacuation position,and a second direction . .defining.!. .Iadd.toward .Iaddend.the fillposition, said valve member having an . .elongated concave surfaceformed at one end thereof and an.!. orifice therethrough providingrestricted communication between said .Iadd.first end of the body andsaid .Iaddend.second end . .and said concave surface, said valve memberoriented within said gas passageway such that said concave surface isdisposed proximate said first end.!. .Iadd.of the body.Iaddend.; and afilter element retainingly held in said passageway . .proximate saidfirst opening, said filter element restricting longitudinal movement ofsaid valve member in the first longitudinal direction of movement.!..Iadd.between said first end and the valve member.Iaddend..
 2. A gaugeblock assembly for a gas transfilling apparatus, the gauge blockassembly comprising:a body having a gas passageway therethrough, saidgas passageway defining a first opening on a first end of said body, anda second opening on a second end of said body; a seat formed within saidgas passageway . .proximate said first end, said seat defined by aradially inwardly extending ledge.!.; a valve member disposed in saidgas passageway and adapted to . .restrictively.!. longitudinally movetherein, said valve member .Iadd.being .Iaddend.restricted inlongitudinal movement in a first direction by said seat. ., said valvemember having a longitudinally extending concave surface formed at oneend thereof, said valve member oriented within said gas passageway suchthat said concave surface is disposed proximate said second end.!.; afilter disposed . .proximate said second end, said filter longitudinallyrestricting movement of said valve member in a second direction.!..Iadd.in the gas passageway between the valve member and said firstend.Iaddend.; means for retaining said filter . .at said second end.!..Iadd.in the gas passageway.Iaddend.; and an aperture formed in saidvalve member providing communication .Iadd.through the gas passageway.Iaddend.between said first end and said second end . .via said concavesurface.!.; said valve member .Iadd.being .Iaddend.longitudinallymovable into a fill position when . .a positive pressure is appliedto.!. .Iadd.pressure at .Iaddend.said second opening .Iadd.is less thanpressure at said first opening .Iaddend.such that said valve memberabuts said seat and said aperture permits . .a.!. .Iadd.gas to flowthrough the gas passageway from the first opening to the second openingat a first .Iaddend.restricted flow rate . .from said second opening tosaid first opening.!., said valve member .Iadd.being.Iaddend.longitudinally movable into an evacuation position when . .anegative pressure is applied to.!. .Iadd.pressure at .Iaddend.saidsecond opening .Iadd.is greater than pressure at said first opening.Iaddend.such that said valve member unseats from said seat and permits. .an unrestricted.!. .Iadd.gas to bypass said valve member aperture andto flow through the gas passageway from the second opening to the firstopening at a second .Iaddend.flow rate . .around said valve member fromsaid first opening to said second opening.!. .Iadd.greater than saidfirst flow rate.Iaddend..
 3. The gauge block assembly of claim 2,wherein said retaining means includes:a radially inwardly projecting ..annular.!. ledge formed within said gas passageway . .proximate saidfirst end, said ledge defining a seat for said filter.!.; and aretaining ring for holding said filter against said ledge, saidretaining ring having .Iadd.at least one .Iaddend.radially outwardlyextending . .flanges.!. .Iadd.flange .Iaddend.that . .abut.!..Iadd.abuts .Iaddend.an inner . .annular.!. surface of said . .secondopening.!. .Iadd.gas passageway.Iaddend..
 4. The gauge block assembly ofclaim 3, wherein . .said negative pressure is supplied by.!. a vacuumpump .Iadd.supplies pressure to move the valve member into theevacuation position.Iaddend., and . .said positive pressure is providedby.!. oxygen under pressure .Iadd.provides pressure to move the valvemember into the fill position.Iaddend..
 5. The gauge assembly of claim2, further comprising:an adjustable valve for controlling the flow ofresidual oxygen from a spent oxygen cylinder that is in communicationwith the gauge block assembly into said valve member; and a meter incommunication with said gas passageway for determining pressure withinsaid gas passageway.